I have a similar line of thought on curtains. I don't plan to change the style, color, etc, every handful of years (or decade). Not every window in this house has curtains yet, and that's because I haven't made (or purchased if I can't make) the ones I want for that room yet.
So, when I made a set of curtains for the master bathroom a year or two after we moved in, I didn't think that I would ever change the window treatment in there.
Until a few weeks ago, when I was doing a semi-annual deep cleaning of the master bath, and washed the curtains. When I took them out of the washer and hung them on the clothesline to dry, I found out I would indeed be getting new curtains.
um, this curtain didn't look like this going into the wash
definitely not going to be putting this one back on the window
I guess the fabric, which had originally been a bed sheet, had sun rotted after all those years of hanging in the window.
I would have to dig through my stash of top sheets and find one to make a new set of curtains with. You see, when I have a set of sheets that the bottom sheet wears out on, rather than throw away the pillow cases and top sheet too, I save them to use the fabric for other projects. There is a whole lot of fabric in a king sized sheet.
It took me a few weeks to actually get around to digging through my stash, but I finally got that new pair of curtains made today. It was pretty easy. They aren't anything fancy.
(And I forgot to take pictures of the process).
But all I did was measure the window top to bottom and side to side, to refresh my memory on how big the curtains needed to be. Then I added two inches to the length for hemming. I didn't add anything to the sides, because I wanted my curtains to be 'bunchy', so extra fabric on the sides was a good thing.
After that, I chose the sheet I wanted to use, and folded it in half side to side (matching the left and right edges from top to bottom). From there, I measured down from the bottom of the doubled over part that makes up the decorative top edge of the sheet, to the length I wanted my curtains to be.
Hope that makes sense. In other words, I didn't start my length measurement at the very top edge of the sheet, but about 4-5" down from the top, where the stitching is. I made this measurement in several spots, putting a light pencil mark at each one, then used a yard stick to draw a line connecting those dots. Following the line with my fabric scissors, I cut the sheet off at that length.
Then I carefully cut up the fold, to make my left curtain and right curtain the exact same width. Again, side to side measurement didn't matter because, since I was using a king sized sheet, I knew I had more than enough fabric there to cover the width of the window.
Now that I had my two pieces to work with, I basted a line 1/2" from the bottom on each piece. Then, like when making my hankies, I folded under and pressed along that line. Unlike the hankies, I folded a second time, to conceal the cut edge. Then I stitched this hem down about 1/4" from the bottom on the 'curtain'.
After the bottoms were hemmed, I made a similar hem on the cut side-edge of each piece. Each piece had one original side hem from the sheet, and I matched the size of that hem, which was 3/8". If you want to make curtains using this method, measure the existing side hem on the sheet you are using, and make the other hem to match.
Now that all the cut edges were finished, it was time to make the rod pocket. I wanted to make mine with a little ruffly part on top, so I folded that decorative finished edge at the top of the sheet on the line of stitching that was there. Then I sewed that down about 3/8" from the part that used to be the top edge. Turning my curtain so that the new top edge lined up with the right edge of the foot plate on my sewing machine, I sewed another line of stitching. This creates the rod pocket with the ruffle above it. If you don't want yours ruffly on top, just skip this second row of stitching.
A quick ironing of each piece, and my new curtains were ready to hang.
(Funky lighting in the picture, the walls aren't peachy, they are beige. And the curtain isn't white, it's pale green with stripes. Although, peachy doesn't look too bad; I might have to reconsider my stance on painting. . . )